Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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812PUSO~g83
FERTILIZER CHIP AND PROCESS
FOR MAKING SAME
FIELD OF THE INVENTION
This invention relates to agricultural fert11izers in chip form and to
a process for producing such fertilizers.
BACKGROUND OF THE INVENTION
The use of various inorganic and organic components which are rich in
phosphorus, potassium and nitrogen as agricultural fertilizers is well known.
Often these components or materials are combined with a binder and pelletized
to facilitate handling, storage and application to agricultural fields.
It has been common practice in the manufacture of fertilizer
compositions to incorporate materials which are by-products from various
processes as a way of converting materials of little commercial value into
fertilizer compositions. Such utilization of by-products not only solves a
disposal problem associated with such by-products, but converts these
generally low value products into products of value. Often there are
associated difficulties in such conversions in that products are not storage
stable, are difficult to handle, or may not be applied to the crops with
conventional equipment.
With respect to the agricultural fertilizer of the present invention,
the following patents have relevancy to the extent that they deal with many
of the components comprised in the agricultural fertilizer. These patents
include the following:
U.S. 242,777 discloses a process for preserving and disinfecting animal
and vegetable substances derived from rendering establishments, sewers,
manure, etc. while at the same time converting the manure and animal
substances into fertilizers which are effective as stimulus to the growth of
vegetation and which are effective as active insecticides. The process
contemplates forming a solution or magma of lava rich in potash by contacting
a lava containing silica, alumina, lime, iron, magnesium and a small
phosphorus with sulfuric acid or hydrochloric acid. The solution is filtered
and the solid residue remaining is removed therefrom. The solution then is
mixed with fecal matter at a maximum of 5 kg filtrate per kg of fecal matter
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and then mixed with empyreumatic lime. This material is mixed and then dried
for conversion into a fertilizer.
U.S. 19,974 discloses a process for condensing and fixing ammonia in
fertilizers for use in the soil. In that process, an aluminous earth
consisting of various silicates of alumina mixed with other silicates; e.g.,
silicate of potash, sodium or silicate of iron, is powdered and made into a
porous bed having access to the free action of air.
U.S. 144,877 discloses methods for producing fertilizers from the
carcasses of tallow-rendering animals. A supernatant liquid obtained from a
tallow-rendering vat is withdrawn from the vat and the water evaporated
therefrom to produce a solution. This liquid then is mixed with Plaster of
Paris for the purpose of combining with the remaining moisture in the syrupy
residue. When allowed to dry, the mixture of Plaster of Paris and tallow
residue is converted into a friable mass which then can be ground to a fine
powder for fertilizer application. Dried clay, chalk and marl are suggested
as possible replacement candidates for the Plaster of Paris.
U.S. 17,237 discloses a process for preparing green-sand-marl
fertilizers. The marl is washed to separate a large amount of alumina and
useless earthy components, leaving the green-sand which then is dried,
pulverized and disintegrated. The green-sand then is mixed with about
600 lbs. of night soil per 1000 lbs. of green-sand and 100 lbs. of sulfate of
lime.
SUMMARY OF THE INVENTION
This invention pertains to a fertilizer and a process for producing the
same which incorporates flyash, which is a by-product from the coal fired
utility industry, with an organic fertilizing component comprising manure.
The flyash and manure are mixed with the resulting mixture compressed into a
sheet and then the resulting sheet fractured into chips.
The invention has significant advantages and these include:
the development of an agricultural fertilizer having excellent
storage stability and handling characteristics;
the utilization of a by-product of the coal-fired electric power
industry into a useful product;
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an ability to formulate an agricultural fertilizer in ~chipU form
which has excellent strength in dry condition, but is readily
friable under moist conditions allowing for dispersion into the
soil and utilization of the nutrients contained therein by crops;
a process which is simple to perform in non sophisticated
equipment.
DETAILED DESCRIPTION OF THE INYENTION
The agricultural fertilizer contemplated here comprises flyash as one
of the components. Flyash is generated in coal-fired power plants, primarily
where the coal is combusted in finely divided form and the flyash
precipitated from the flue gases. The particle size of such flyash is
generally between about 100 to 325 mesh U.S. standard sieve. Flyash is
predominantly silica and alumina with large amounts of iron oxides. As might
be expected from a silica containing product, flyash is somewhat glassy in
appearance because of the high temperatures reached in the combustion process.
The other primary component of the agricultural fertilizer is manure,
and that term requires little description. Virtually any manure may be used
for combination with the flyash, although it is preferred that the manure be
essentially free of extraneous fibrous material such as straw, chaff, and the
like. Manure from chickens, sheep and other ruminants is desirable for
preparing the agricultural fertilizer.
Other additives conventionally used in fertilizers may be incorporated
into the agricultural fertilizer, and these include nitrogen, phosphorus,
potash providing components, as well as insecticides and specialty herbicides.
Examples of fertilizer components include ammonium nitrate, ammonium
phosphate, ammonium sulfate, pH adjustment additives such as calcium
carbonate, etc. Insecticides include thiocarbamates, an example being sold
under the trademark, Sevin; chlorinated organics, and diazinone. Virtually
any of the specialty herbicides may be combined with the fertilizer batch in
amounts as desired.
In formulating the fertilizer, a master formulation is prepared by
mixing the flyash with the manure and other preselected fertilizer components
thereby creating a blend. The liquid, primarily water, concentration of the
blend should be controlled such that from about 5% to 28% by weight of the
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batch is liquid or water. Such liquid or water content will leave the
resulting blend in the form of a thick paste having a consistency similar to
peanut butter. If too much water is present in the resulting blend, problems
are associated with the sheet-forming step with residual water being squeezed
from the resulting mixture during pressing and sheet forming. Too little
water results in a paste having insufficient binding attraction for enhanced
sheet formation.
In the processing of the blend to form a storage-stable, high strength
chip, which is easily handled during storage and easily handled for
application to crops, the blend is formed into a sheet and the resulting sheet
fractured into small chips. One method of sheet formation is accomplished by
passing the blend through a roll press under a compression load of from 4 to
20 tons force per linear inch of sheet width. Typically a roll speed of 1 to
10 linear feet per second is made during compaction, thus providing a
residence time of from about 0.1 to 0.~ seconds. Generally, the roll faces
are maintained at elevated temperature; e.g., from 25C to 135C. High
temperature generally ought to be avoided since the high temperature also
results in the liberation of ammonia from the blend, thereby decreasing its
nitrogen imparting characteristics. To facilitate compaction and compression
in the roll press, the blend may be conveyed to the roll press via a screw-
type conveyor which delivers the blend in relatively compact form to the
compression rolls. As the blend of flyash and manure, optionally including
other fertilizer components, is fed to the compression roll, the blend is
formed into a thin sheet; e.g., from about 0.08 to 0.54 inches in thickness.
Because of the high compression pressures, the manure and flyash bond through
physical attraction for providing chip form product having excellent dry
strength.
The sheet can be fractured into chip utilizing a wide variety of
mechanical apparatus or chips can be ground or fractured allowing the sheet
from the compression rolls to fall onto a conveyor, with the falling onto the
belt causing the sheet to fracture. Supplemental crushing can be conducted,
if required. The resulting chips have a size of from about 1/4 to 1 inch on
a side when dried and have excellent strength for promoting storage stability
and handling.
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The following examples are provided to illustrate various embodiments
of the invention and are not intended to restrict the scope thereof.
Example 1
Trial Procedure for producinq Chip Form Fertilizer
A series of tests were carried out in order to produce "chip" form
agricultural fertilizers from flyash and a straw free cow manure. The roll
press used in the process was a Komarek lab compactor; a granulating unit
having a 3/8" open screen was also used.
In general a blend was prepared by mixing a flyash with manure with the
weight percent of flyash being about 70% and the manure being about 30%.
These materials were blended in a Beardsley and Piper Speed Mullor Mixer,
Model 45B having an 18-inch drive with 10-inch straight side with a scraper
and muller operating at 400 rpm. The blend was densified via a densifying
screw press and then introduced to a variable speed vertical double roll
compactor, said compactor having smooth roll surfaces. The rolls were 2
inches wide and had a 5 inch diameter. The roll separating force ranged from
about 4 to 9 tons per linear inch of roll face with the roll speed ranging
from 6 to 11 rpm. The temperature of the roller face approached 135 F causing
an evolution of ammonia and urea. A sheet having a thickness of about 0.25
inches was generated and was comminuted into chip form product using a Model
DAS 06 Knife Comminutor. The chips were about 1/8 inch in thickness and had
irregular planar dimensions of about 1/2 to 1 inch. The chips then were
ground in the comminutor to produce a product having a mesh size of 4 to 30
US mesh.
More specifically, the feed was prepared in an amount of 280 lbs flyash
and 120 lbs of cow manure. The manure was placed in the mixer and initially
mixed for 5 min. After that, the fly ash was added and mixing was continued
for an additional 5 min. Then water in preselected amounts was added and the
blend mixed for an additional 10 min. The blend was the compacted and
processed as described above. Table 1 below set forth the general processing
conditions and results.
TABLE 1
Run Flyash % Manure % Moisture Blend Roll Thickness Force Description
g/cc RPM mm MN/m
1 70 30 14.1 0.89 6 3.5 1.39 Strong, stable
2 50 50 14.1 0.94 10.8 1.3 1.39 Weak, friable
3 80 20 15.1 0.8 10.8 2.9 1.39 Medium strong,
4 100 - 5.0 0.68 6 2.7 1.39 Poor chips
CaS04 9.4 0.6 6 2.9 1.39 Strong, stable6 100 12.0 0.87 6 3.3 1.39 Poor strength
7 100 6 Brewex* 7.2 0.64 6 2.9 1.39 Medium strong
8 100 9 Brewex 10.1 0.8 8.2 2.9 1.39 Very strong and ~~'
9 70 30 25.8 0.87 0.87 2.9 1.39 Strong and stable O
*Brewex is a trademark for a modified starch containing 47% malto dextrins, 33% maltose, 10% glucose,
6% protein and 4% ash.
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